Related papers: Two-photon absorption in silicon using real densit…
Discovery of high-performance materials remains one of the most active areas in photovoltaics (PV) research. Indirect band gap materials form the largest part of the semiconductor chemical space, but predicting their suitability for PV…
Several classical analogues of electromagnetically induced transparency in metamaterials have been demonstrated. A simple two-resonator model can describe their absorption spectrum qualitatively, but fails to provide information about the…
Silicon photonics is being extended from the near-infrared (near-IR) window of 1.3-1.5 {\mu}m for optical fiber communications to the mid-infrared (mid-IR) wavelength-band of 2 {\mu}m or longer for satisfying the increasing demands in many…
Here we perform a series of time-resolved experiments where a 100 fs pump pulse is tuned between 528 nm and 555 nm, across the second indirect gap of intrinsic silicon at ~540 nm which involves electrons in a higher-lying conduction band…
We calculate the rate of two-photon absorption for frequency entangled photons in a tapered optical fiber whose diameter is comparable to the wavelength of the light. The confinement of the electric field in the transverse direction…
We measure the absolute absorption cross section of molecules using a matter-wave interferometer. A nanostructured density distribution is imprinted onto a dilute molecular beam through quantum interference. As the beam crosses the light…
Recent breakthroughs in cryogenic silicon detector technology allow for the observation of single electron-hole pairs released via particle interactions within the target material. This implies sensitivity to energy depositions as low as…
Using an Electrically Focus Tunable Lens (EFTL), an integrating sphere and a tunable femtosecond-pulse laser (Mai Tai HP), we were able to measure the degenerate two-photon absorption coefficient (in transmission) of CdS and ZnSe in a long…
We report on the response of graphene to high intensity mid-IR radiation and show that graphene exhibits saturable absorption and significant two-photon absorption in the spectral region from 1.55 $\mu$m to 3.50 $\mu$m (0.35 eV to 0.80 eV).…
We investigate the non-linear response and energy absorption in bulk silicon irradiated by intense 12-fs near-infrared laser pulses. Depending on the laser intensity, we distinguish two regimes of non-linear absorption of the laser energy:…
We introduce a real-space approach to understand the relationship between optical absorption and crystal structure. We apply this approach to alternative phases of silicon, with a focus on the Si$_{20}$ crystal phase as a case study. We…
Despite the decades that have passed since the discovery of ultrafast transient absorption spectroscopy and its apparent simplicity, this method is still often subject to experimental errors and misinterpretations when applied to 2D…
Imaging at depth in opaque materials has long been a challenge. Recently, wavefront shaping has enabled significant advance for deep imaging. Nevertheless, most non-invasive wavefront shaping methods require cameras, lack the sensitivity…
The positive effects of various perturbations introduced in a bidimensional photonic-crystal patterned membrane on its integrated absorption are investigated numerically and theoretically. Two phenomena responsible for the enhanced…
Understanding exciton-defect interactions is critical for optimizing optoelectronic and quantum information applications in many materials. However, ab initio simulations of material properties with defects are often limited to high defect…
We experimentally demonstrate that the addition of partial lattice disorder to a thin-film micro-crystalline silicon photonic crystal results in the controlled spectral broadening of its absorption peaks to form quasi resonances; increasing…
Silicon's inherently indirect bandgap severely limits its radiative efficiency, posing a fundamental challenge to the development of practical silicon-based light sources. While strategies such as nanoscale confinement of electrons and…
We report on very high enhancement of thin layer's absorption through band-engineering of a photonic crystal structure. We realized amorphous silicon (aSi) photonic crystals, where slow light modes improve absorption efficiency. We show…
We address the textbook problem of dynamics of a spin placed in a dc magnetic field and subjected to an ac drive. If the drive is polarized in the plane perpendicular to the dc field, the drive photons are resonantly absorbed when the…
We demonstrate and study the enhancement of intermediate-field two-photon absorption by shaped femtosecond pulses having spectral phases of antisymmetric nature. The intermediate-field regime corresponds to pulse intensities, where the…